30000m~3/h空分设备氩气回收系统的投用和改造

南钢制氧厂30000 m3/h空分设备的1000 m3低温液氩贮槽配备了氩气回收系统,但启用后造成了1000 m3低温液氩贮槽被污染和精氩塔氮含量偏高的事故,检修并改造管路系统后氩气回收系统运行正常。介绍氩气回收系统的流程和管路检修、改造方案。     

泵供液制冷系统低温管道保温厚度的优化

建立典型的氨泵供液单级压缩制冷系统和氨泵供液双级压缩一次节流中间完全冷却制冷系统的吸气管、回汽管等低温管道的传热数学模型和低温管道年总消耗费用的经济模型.基于传热模型、经济模型和氨的热力特性模型,用VB6.0语言分别编制适合于氨泵供液单级和双级压缩制冷系统低温管道保温层厚度的优化设计程序.利用优化程序对厦门地区某大型水产冷库低温冷藏库回路的低温管道保温层厚度进行实例优化设计计算,结果表明:与传统设计方法选用的保温厚度比较,程序选用的最佳经济厚度可使管道的年总消耗费节省5.4%.     

平板速冻三种供液方式的实验比较

本文提出了一种射流泵节流供液制冷系统（方式III）,并与传统的热力膨胀阀供液（方式I）和液泵供液（方式II）进行了实验对比,研究了三种供液方式对模拟食品的冻结时间、冻品温差和冻结装置总能耗的影响。结果表明,在本文的实验条件下,方式II和方式III比方式I的冻结时间缩短了约14%,模拟食品的温度下降更为均匀,有利于冻品质量的提高。在能耗方面,方式III比方式I节省了6.3%,比方式II节省了9.6%。因此,射流泵节流供液优势明显。     

The control of paracetamol particle size and surface morphology through crystallisation in a spray dryer

The parameters governing the crystallisation of paracetamol using various conventional techniques has been extensively studied, however the factors influencing the drug crystallisation using spray drying is not as well understood. The aim of this work was to investigate the crystallisation of an active pharmaceutical ingredient through evaporative crystallisation using a spray dryer to study the physicochemical properties of the drug and to use semi-empirical equations to gain insight into the morphology and particle size of the dried powder. Paracetamol solutions were spray dried at various inlet temperatures ranging from 60 °C to 120 °C and also from a series of inlet feed solvent compositions ranging from 50/50% v/v ethanol/water to 100% ethanol and solid-state characterisation was done. The size and morphology of the dried materials were altered with a change in spray drying parameters, with an increase in inlet temperature leading to an increase in particle Sauter mean diameter (from 3.0 to 4.4 µm) and a decrease in the particle size with an increase in ethanol concentration in the feed (from 4.6 to 4.4 µm) as a result of changes in particle density and atomised droplet size. The morphology of the dried particles consisted of agglomerates of individual crystallites bound together into larger semi-spherical agglomerates with a higher tendency for particles having crystalline ridges to form at higher ethanol concentrations of the feed.